Stepped beam slot antenna array



March 28, 1967 1 .'r1-1oUR1-:L

STEPPED BEAM SLOT ANTENNA ARRAY 2 Sheets-Sheet 1 Filed July 31. 1964 f, 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 75| I 1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 llllllllllllllllllllll Illlllllllllllllllllll' fm l 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 F165v I FIG.5

FIG.4

United States Patent O 3,311,917 STEPPED BEAM SLOT ANTENNA ARRAY Leo Thourel, Paris, France, assignor to CSF-Compagnie Generale de Telegraphie Sans Fil, a corporation of France Filed July 31, 1964, Ser. No. 386,553 Claims priority, application France, Aug. 6, 1963, 993,822, Patent 1,373,111 2 Claims. (Cl. 343-754) The present invention relates to antennas of the type used in three-dimensional radars. Such antennas are zgenerally capable either of simultaneously radiatin'g a plurality of beams stepped in elevation or of radiating a single beam, or a plurality of beams, for scanning space in elevation.

The radiator of such antennas is generally lvery vulnerable in particular, if shock Waves occur in the ambient medium.

It is an object of the invention to provide an antenna for three-dimensional radars which is free of 1this drawback.

An antenna according to the invention consists essentially of a flat structure which can be used with circuits, which are put in the ground. It comprises slot Waveguides, arranged in parallel relationship in one plane, means being provided for varying the phase of the Waves fed thereto.

The invention Will be better understood from the following description with reference to the appended drawings, in which:

FIG. 1 and FIG. 2 show two types of radiation patterns used in three-dimensional radars;

FIG. 3 is a 'top view of one embodiment of the antenna according to the invention;

FIGS. 4, 5, 5a and 6y are explanatory figu'res;

FIG. 7 is a top view of a further antenna according to the invention; and

FIG. 8 is a side view of the -arrangement of FIG. 7.

FIG. 1 shows one type of the beam radiated by an antenna for |three-dimensional radars. This beam is contained in the plane zOx, Oz being the Vertical and x, and Oy the horizontal axes forming a trirectangular trihedral.

The beam makes with Ox an adjustable angle 0 which depends, for example, on the phase Velocity of the energy in a radiating line.

FIG. 2 shows another type of radiation pattern, consisting of five beams stepped vertically in plane zOx.

FIG. 3 shows an antenna according to the invention.

It comprises n parallel and coplanar identical radiating waveguides laterally contacting each other. These Waveguides are provided with slots F, the whole thus forming a rectangular radiating plate.

If the slots are fed in phase, the resulting radiation lobe is direoted along Oz, i.e. perpendiculafr to the plane yOvc of the plate, 0x being the direction of the Waveguides.

But, if waveguide 1 is fed With a phase O, waveguide 2 with a phase p, waveguide P With phase op, and if:

the radiation is directed 'in plane zOy and makes an angle 0 with Oz, 0 being a function of p, as shown in FIG. 4.

These phase-shifts can be obtained, -for example, by means of ferrite phase Shifters D, inserted at the input of each waveguide. The scanning in elevation is thus made possible.

The waveguide system is fed through a lens L and a horn C. The horn is excited at the focus of the lens.

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All the guides are fed in phase and the phase difference between .the individual guides is achieved by means of phase-Shifters. Other means may be used.

In FIG. 5, which shows another embodiment of the invention, lens L is excited by three horns: horn F1 is placed at the lens focus and horns F2 and F3 in the focal plane of the lens and are offset with respect to the focus by a distance D.

FIG. 5a shows the curve connecting points with the same phase at the lens output when the lens is illuminated by horn F3.

If the three horns are excited simultaneously, there will be a system of three beams, one for each horn, in plane zOy.

FIG. 7 shows one embodiment of the invention comprising no lens.

A sectoral horn S is fed by four horns F1, F0, F2 and F3 which supply the four beams stepped in elevation, as shown in FIG. 6. A suitable adjustment of the phase Shifters D provides the desired steps and electr-ically operated phase Shifters E ensure scanning in elevation.

-FIG. 8 shows, very diagrammatically, a cross-sectional view of one embodiment of the invention including a transmitter-receiver ER, which is located in a pit under waveguide G, and supported on a framework which can 'be made to rotate by means of Wheels R on a platform.

This framework is designed to stand substantial pressures, for example up to 1.4 kg. per cm.2 when -a shock Wave occurs. To this end the surface of the waveguides is protected by multi-layer plastic flags which resist heat. The platform is adavntageously made of a refractory, shock absorbing material.

Of course, the invention is not limited to the embodiments desoribed and shown which were given solely by way of example.

What is claimed is:

1. An antenna for radiating ultra-short electromagnetic Waves comprising: a plurality of parallel and coplanar wave guides having radiating slots and respective inputs; a lens for electromagnetic Waves facing said inputs, said lens having a focal plane; in said plane a plurality of horns for feeding energy to said inputs with a plurality of respective identical phases; and controllable phase shifting means in said guides at said inputs.

2. An antenna for radiating ultra-short electromagnetic Waves comprising: a plurality of parallel and coplanar wave guides having radiating slots and respective inputs; means for feeding energy to said inputs with the same phase said means comprising at least two sources supplying at least two stepped lobes, a horn coupled between said sources and said wave guides and first controllable phase shifting means in said guides at said inputs for adjusting the radiation pattern; and second controllable phase shifting means for scanning space with said lobes.

References Cited by the Examiner UNITED STATES PATENTS 3,020,549 2/1962 Keles et al. 343-853 X 3,041,605 6/1962 Goodwin et al. 343-854 X 3,213,454 10/1965 Ringenbaoh 343-771 X FOREIGN PATENTS 882,430 7/ 1953 Germany.

ELI LIEBERMAN, Primary Examiner.

HERMAN KARL SAALBACH, Examiner.

R. F. HUNT, Assistant Examiner. 

1. AN ANTENNA FOR RADIATING ULTRA-SHORT ELECTROMAGNETIC WAVES COMPRISING: A PLURALITY OF PARALLEL AND COPLANAR WAVE GUIDES HAVING RADIATING SLOTS AND RESPECTIVE INPUTS; A LENS FOR ELECTROMAGNETIC WAVES FACING SAID INPUTS, SAID LENS HAVING A FOCAL PLANE; IN SAID PLANE A PLURALITY OF 